Q24 / 160 · AP EAMCET 2019 (20 Apr Shift 2) · Chemistry

Which of the following statements is not correct?

  • A
    Both physical and chemical adsorptions are exothermic
  • Correct answer
    B
    Physical adsorption takes place with decrease of free energy whereas chemical adsorption occurs with increase of free energy
  • C
    Physical adsorption requires low activation energy but chemical adsorption requires high activation energy
  • D
    The magnitude of chemical adsorption increases and that of physical adsorption decreases with rise in temperature

Solution

Both physical and chemical adsorption are exothermic in nature. But, chemical absorption requires high heat of adsorption due to formation of chemical bond. Moreover, magnitude of chemical adsorption increases and that of physical adsorption decreases with the rise in temperature due to requirement of activation energy in case of chemical adsorption. Thus, option (b) is incorrect.

Hence, the correct answer is option: 'B'.

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